Shear All Ram features curved asymmetrical blades
The Shear All Ram (SAR) was introduced last week at OTC, a BOP ram design whose field tests show it has the ability to shear “any size pipe and casing with 30% to 50% less shearing force (than conventional rams)” and “to manipulate the pipe or the casing, centering the pipe or casing for a clear decisive shear,” Saeid Rahimian, president of the fluid management group for Robbins Myers, said at the product launch during the Offshore Technology Conference in Houston last week.
SAR is expected to be offered by Robbins Myers’ T3 Energy Services unit in Q3 this year.
“This is probably the only shearing device that wholly sweeps the bore of the blowout preventer to assure that it gathers up the pipe, moves the pipe to a shearable position, and then of course continues on and shears the pipe,” T3 VP engineering Gary Schaeper said, adding that SAR development is an ongoing process. “We’ve yet to find the limit. We haven’t broken the rams yet. … We have a lot more development work to do to find the limit to this product.”
According to Doug Jahnke, engineering manager for T3’s pressure control group, the asymmetry of the design is the product’s most unique feature, allowing for more blade features in a smaller envelope. “Incorporating a near-vertical rake promotes tensile failure at the creasing points. The blade arcs extend forward to provide containment, supported transversely against the side of the ram bore, so there’s no fear of breaking the sides off,” Mr Jahnke said. Due to the ram’s architecture, it also allows the sheared pipe to be lifted out of the BOP so it doesn’t interfere with the further closure of the rams, he said.